Columbia is second only to Brazil in terms of biodiversity, and no less than 37 different species of primate are found within its borders. With the destruction and fragmentation of forest cover, many of these species are increasingly threatened, especially those with small geographic ranges. The Silvery Brown Tamarin is found only in the Central Magdalena valley, and none of its range is inside a protected area at present. It is also the target for a large internal pet trade in wild caught animals, and is currently the most confiscated animal to be found in Columbia rescue centres. Historically, survival rates have been very poor, as a result of lack of knowledge of their requirements and capture stress (many species of marmoset and tamarin are very sensitive to this). As a result of this, the population in the last 18 years is estimated on the IUCN Red Book to have declined by over 50%, and it is classed as Endangered.
In 2006 Bristol and other European zoos in the Callitrichid Taxon Advisory Group began a cooperative venture to foster the conservation of the tamarin. Efforts have been focussed on studies of animals in the wild, and improving care and possible captive breeding programmes in both Columbian and other zoos. So far seven zoos in Columbia hold the species, and there have been some births, but work still needs to be done. Experience with the Lion Tamarins shows that this kind of programme can be successful, but is a long struggle to get to a point where the species can be reintroduced to the wild. Columbian law is rigid in the regulations concerning the transfer of any of the rescue animals out of the country, so we are unlikely to see them at Bristol any time soon – we will have to wait until animals at least 2 generations from the wild founders are available. I have however found a film of one on Youtube here: http://www.youtube.com/watch?v=G5vW6n148N8
Despite their high diversity, the various small callitrichids have fairly similar social structures. A group will be centred around a single breeding female and her mate, plus offspring of various ages. The young are carried by the adult male and their older siblings until they become independent at a few months old. The main difference between marmosets and tamarins lies in their feeding ecology – marmosets have specialised dentition which enables them to gouge grooves in the bark of trees to release sap and gum, which are major components in their diet. Tamarins lack the gouging jaws, so can only use pre-existing wounds in trees as a source of this food. Aside from this, both groups feed heavily on insects, especially orthopterans, and also catch frogs and lizards, and raid birds nests. They will also take some fruit, and where forest edge meets agricultural land they will raid fruit trees. Differences between species, which often move in mixed species groups, centre on the proportions of the various dietary elements and the parts of the trees from forest floor to canopy that they use.
In captivity, most marmosets are now supplied with a diet that is tailored to meet nutritional needs. Developing a diet for a captive animal is quite a tricky process, as even when you know what an animal feeds on in the wild you generally do not have enough knowledge of how the wild food source compares nutritionally with that available in captivity, even if for example you are feeding the same plant, as growing conditions, soil composition, even the time of year can all affect results. The Callitichid husbandry manual has a long chapter on diet for callitrichids, which lists nutrient requirements as follows:
Nutrient Concentration in diet*
Energy (kcal/g) **
Crude protein (%) **
Fat (%) —
Fiber (%) —
Linoleic acid (%) 1
Vitamin A (IU/g) 14
Vitamin D (IU/g) 2.2 or less
Vitamin E (mg/kg) 56
Thiamin (mg/kg) 5.6
Riboflavin (mg/kg) 5.6
Niacin (mg/kg) 55.6
Pyridoxine (mg/kg) 2.8
Folacin (mg/kg) 0.2
Vitamin B12 (mg/kg) 0.6
Pantothenic acid (mg/kg) 16.7
Choline (mg/kg) —
Biotin (mg/kg) 0.1
Vitamin C (mg/kg) 500 or more
Calcium (%) 0.6
Phosphorous (%) 0.4
Magnesium (%) 0.2
Potassium (%) 0.9
Sodium (%) 0.3
Iron (mg/kg) 200 or less (80-200)
Zinc (mg/kg) 11.1
Copper (mg/kg) 1.5
Manganese (mg/kg) 44.4
Selenium (mg/kg) —
Iodine (mg/kg) 2***
* Probable requirements for New World primates. Depending on the interpretation of the NRC (1978), the requirements for magnesium, iron, and manganese may be overestimated.
** The requirements for these nutrients are higher for marmosets and tamarins than for other New World primates. Energy required is 150-160 Kcal/Kg body mass/day (d) (Morin 1980); protein for small primate species is 3.5- 4.5 g/Kg body mass/day of high-quality protein (NRC 1978); vitamin D3 required is 110 IU/d/100 g body mass (Takahashi et al. 1985).
*** NRC may have overestimated the quantity needed. For most other animals the requirement is about 0.1.
— No NRC requirement stated for this nutrient. This does not mean there is no requirement, just that studies have not been performed. For selenium, the level in many mammals is about 0.1 ppm.
With this as a basis, several different usable diets have been formulated. As marmosets have been used as laboratory animals, specialised commercial diets are available which can be adapted to other callitrichid species. Examples of these diets can be found in the husbandry manual, which is available here: http://nwptag.com/Download%20Text.htm. Even this has a lot of space for variation – for example ‘fruits’ in a captive diet in the UK will usually be apple, pear, grape, or other similar plants grown in the UK. In the native Columbia, fruits available in a typical market might include guava, prickly pear, passion fruits (of several species), cherimoya, papaya, tomatillo or many others. How these compare and interact with other diets is a major research item for an animal collection, and nutritionists are still developing recommendations. For example, high dietary vitamin C in birds and probably some mammals promotes iron absorption, which can lead to liver problems in animals used to low iron diets in the wild.
For the Silvery Brown Tamarin the year has started well, with the association of South American Zoos and Aquaria (ALPZA) accrediting the programme as a cpnservation leader for South American zoos. For more information, check out the ALPZA website at http://www.alpza.com/
Next week, we move on to the larger primates, starting with one of the most iconic of South American monkeys, the Spider Monkeys
Information and images from Bristol Zoo website, ARKive, ALPZA
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